Coffee Has-Beans Remove Heavy Metals from Water


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Categories: Health & Nutrition

Main heavy metals contamination of water is a serious threat to the globe ecosystem. Many industries such as metal plating, mining operation, and tanneries release waste waters contaminated with heavy metals into the environment. So, their removal from contaminated waters has become a major topic of research in recent years, due to the toxicological problems caused by the metal ions to the environment and to human health. Various processes of heavy metals elimination are used, such as precipitation, electro precipitation, electro coagulation, cementing and separation by membrane, the solvent extraction and the exchange of ions on resins.

However, these processes are not economical OPEN ACCESS Materials enough for waste water treatment. Strict environmental protection legislation and public environmental concerns lead the global search for novel and low-cost techniques to remove heavy metals from industrial waste water. So, recent research is directed to developing cost-effective technologies for the removal of metal ions from aqueous solutions. Adsorption is considered to be quite attractive in terms of its efficiency of removal from dilute solutions. Although the use of common materials (activated carbon, chitosan, zeolite, clay) is still very popular due to the high adsorption capacity, they are expensive, too.

Thus, there is a growing demand to find relatively efficient, low-cost and easily available adsorbents for the adsorption of heavy metals, particularly if the adsorbents are the wastes. Researchers were oriented towards no expensive adsorbents. However, there is a lack of literature dealing with the possible application of commercial coffee wastes as adsorbents. Under the title of “coffee wastes” are generally called the solid wastes discarded from the extraction process of instant coffee manufacturing, and the final residues originated from cafeterias.

A team of Italian scientists has used old coffee grounds to create a foam that can get rid of lead and mercury from water.


Despite the fact that coffee grounds can be a helpful addition to compost or gardening mixes, a large amount of the leftovers from one of the world’s favorite beverages still ends up in landfill. Once there, the grounds decompose, producing the greenhouse gas methane.

Given that our thirst for coffee isn’t likely to die down anytime soon, ideas for sustainable methods of recycling and upcycling old coffee grounds (and the takeaway cups that coffee is sometimes served in) are taking shape. Scientists have been analysing its effectiveness in water remediation and have had some success in using it to remove heavy metal ions from water. Researchers from the University of Genoa and the Italian Institute of Technology recently took this research a step further, looking to simplify the process and develop a way to remove the coffee powder from water once it had done its job. The result is a foam (or sponge) made out of old espresso coffee grounds, silicone and sugar that could act as filters.

When dipped in still water, the foam removed 99 per cent of lead and mercury after 30 hours which sounds great on paper but of far more interest (and potential greater impact) is the test they performed with flowing, lead-contaminated water, where the team found that the foam could remove 67 per cent of lead.

This is not the first time waste has been used to remove heavy metals from water. In 2015, a team of Australian scientists developed a polymer made using waste from the citrus and petroleum industries that could remove mercury from water. These “two-birds-with-one-stone” approaches could provide a solution to certain waste management issues while simultaneously making clean drinking water more widely available.

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